Geothermal energy has been used in one form or another for many thousands of years to make life better. Beginning with early hot springs that were valued for their curative or restorative properties and continuing today with geothermal electrical generation at geothermal hotspots, this energy source has been valued for its renewability and low environmental impact.
Turning specifically now to generation of electrical power by geothermal means, possibly the most common approach is to utilize hot water and/or steam that originates beneath the surface of the earth into a heat exchanger or a turbines, etc. with the goal of generating electric power. Typically, these sorts of power plants are large-scale operations that are situated near geothermal hot spots. Obviously, such large-scale facilities are best situated near a correspondingly large near-surface heat source, of which there are not that many candidates. For example, Yellowstone National Park would be a tremendous source of geothermal energy but is off limits to commercial development for obvious reasons.
This fact (i.e., the relative rarity of near-surface geothermal heat sources) has made utilization of this source of energy for power generation problematic. Of course, the general scarcity of geothermal hot spots near population centers has made it correspondingly more difficult to attract the funds that would be necessary to build a generating plant at a remote location and transmit the power to the consumers that need it.
That being said, those of ordinary skill in the art will recognize that it is possible to find extremely high subsurface temperatures almost anywhere if a sufficiently deep penetration into the subsurface available. Of particular interest for purposes of the instant application are wells that might have been drilled to depth specifically for purposes discussed hereinafter or, possibly, hydrocarbon (e.g., oil and/or gas) wells that might either be wells that have exhausted their oil source or wells that failed to uncover any petroleum deposits at all depths (e.g., dry holes). These sorts of abandoned or otherwise available well shafts provide access to the deep subsurface where temperatures at the bottom might be well above the boiling point of water at atmospheric pressure (e.g., 212° F. or 100° C.). In fact, and depending on the local geothermal gradient, a well of depth 10,000-20,000 feet is likely to encounter temperatures more than sufficient to boil water and, in many cases, temperatures high enough to superheat water.
However, one problem with utilizing the thermal energy that might be available at the bottom of such wells is that existing approaches are not well suited to exploiting geothermal energy on such a small scale. That is, in order to be economic conventional geothermal power plants require a substantial heat source that can continuously produce a high quantity of steam for a long period of time. But, preexisting deeply penetrating wells are typically not drilled close enough together to likely be of much use in this context. Further, even if there are multiple wells located in close proximity the economics of collecting, collating, and transporting the steam from the wells to the generator will make the project uneconomic. On the other hand, there are large numbers of individual abandoned wells that, if the technology existed, could be relied upon to produce steam or superheated steam on a small scale.
Thus, what is needed is a system and method that would make it possible to utilize the extreme temperatures that are available in individual, deeply drilled wells for purposes of power generation.
Heretofore, as is well known in the power generating arts, there has been a need for an invention to address and solve the above-described problems. Accordingly, it should now be recognized, as was recognized by the present inventor, that there exists, and has existed for some time, a very real need for a system and method that would provide small scale power generation from a single or very small number of individual wells.
Before proceeding to a description of the present invention, however, it should be noted and remembered that the description of the invention which follows, together with the accompanying drawings, should not be construed as limiting the invention to the examples (or preferred embodiments) shown and described. This is so because those skilled in the art to which the invention pertains will be able to devise other forms of the invention within the ambit of the pending claims.